The advance of hydraulic fracturing in North America has given rise to certain wellhead equipment and services. Production decline rates of many frac wells often lead to the use of artificial lift after a period of initial flowback and production. A frequent method of artificial lift implemented is a rod pump. In this case, the tubing string is placed in tension, helping align the string to prevent contact and wear between the outer diameter of the rod and the inner diameter of the tubing. This tension can be achieved by using a tension hanger.
A tension hanger is fundamentally a two piece mandrel hanger, with an inner mandrel bushing connection to a parent body housing. Typically the hanger is initially landed in the bowl. At this point the landing position of the tubing is marked at the top of the BOP. The inner mandrel and parent body connection is then broken, allowing the mandrel to run downhole for the setting of the packer, while the parent body remains in the bowl. Once the packer is set, the mandrel is raised back up and reconnected to the parent body with the string now in tension, with the final landing position matching the initial, confirmed by the tubing marked at the top of the BOP.
As an alternative to a mandrel, a string can be put in tension with slips, or connected directly to the adapter with an iterative process using specific length pup joints, but either does not permit the use of a back pressure valve, a growing and often customer mandatory preference. The recent increase in the shale drilling activity, combined with typical rapid production decline rates, makes a new well likely to soon require artificial lift, and in turn, putting the string in tension.